In order to activate/inactivate carotid baroreceptors (CBA/CBI) we used a neck chamber to produce neck suction/pressure. CBA was evoked by the applicationof a negative pressure to the neck, whereas CBI was produced by applying positive neck pressure. We continuously measured the heart rate (expressed by the R-R interval). The increase in heart response (GHR) was determined from changes in the R-R-interval in response to neck suction/pressure. The cardiac baroreflex was significantly decreased in patients with the obstructive sleep apnea syndrome (OSAS), in comparison with the control group (C). Thus, baroreflex subsensitivity in OSAS patients could increase sympathetic activity, resulting in arterial hypertension. This work was supported by the grant of the State Committee for Scientific Research, Warsaw, Poland.

Keywords: Hypertension, carotid cardiac baroreflex in humans, obstructive sleep apnea